Most Frequently Asked Questions: Spring

When is the optimal time to transplant evergreens and deciduous plants?
In our area, USDA Zone 6a/6b, most deciduous woody plants can be planted and transplanted during the spring season between March 15 and May 1, before growth begins, or the fall planting season during dormancy between October 15 and December 1. Certain deciduous trees only transplant well in the spring planting season; some of these species include Beech, Birch, Maple Oak, and Sweetgum.

Evergreen trees and shrubs are best planted in the early spring between March 1 and April 15, prior to new growth, or mid- August through October 1 after growth has subsided and the ground is conducive toward easy root establishment. (Do not plant evergreens in late fall, as they will not have time to harden off before the damaging frost and winter winds arrive).

Transplanting is a shock to living plants and certain compensatory measures will help reduce the level of disturbance experienced by the plants. Judicious pruning at the time of planting will help compensate for root damage. Give appropriate attention to watering immediately after planting, and often, sometimes daily, to establish the new root system. Provide an organic mulch at the soil level to help conserve moisture.

Be sure that planting conditions are suitable; do not plant if the ground is excessively wet or frozen.

When is the best time to transplant houseplants?
The optimum time for transplanting is at the beginning of active growth, which for most tropical houseplants is in spring. The exception to this are winter-blooming houseplants such as Jasmine and Amaryllis that are best potted in the fall after their dormant period. Some houseplants just like to grow potbound and resent being moved altogether. Rather than repotting plants such as Clivia and Fern, let them remain in a maximum size pot and topdress annually with a sterilized houseplant potting soil.

How do I prepare shrub and tree holes for planting?
For bare-root plants, soak the roots in warm water for several hours to re-moisturize the cells. Dig the hole and determine the proper planting depth by noting the color difference at the juncture of the main stems and the roots. Spread out the roots and backfill the hole with the removed soil mixed with amendments such as compost. Water thoroughly and create an earth saucer around the plant to hold and direct water to the roots. Give appropriate attention to watering immediately after planting and often, sometimes daily, to establish the new root system. Provide an organic mulch on the soil to help conserve moisture.

For container-grown stock, remove the plant from the container even though the label may state otherwise. So-called plantable or biodegradable containers prevent roots from penetrating out from the container wall. If the plant is root bound, cut through the root mass on several sides and pull out roots to give more room. Dig the hole to a depth equal to the height of the container and twice as wide. Place the root ball in the hole and backfill with removed soil amended with compost. Carefully tamp down the soil in six-inch layers, water thoroughly and create an earth saucer around the plant to hold and direct water to the roots. Give appropriate attention to watering immediately after planting and often, sometimes daily, to establish the new root system. Provide an organic mulch at the soil level to help conserve moisture.

For balled and burlap plants, dig the hole as deep as the ball and twice as wide. Set the plant in the prepared hole and remove the synthetic "burlap" wrapping material from the root ball. Backfill with removed soil amended with compost. Carefully tamp down the soil in six-inch layers, water thoroughly and create an earth saucer around the plant to hold and direct water to the roots. Give appropriate attention to watering immediately after planting and often, sometimes daily, to establish the new root system. Provide an organic mulch on the soil to help conserve moisture.

Why do I need to use compost in the garden and can it replace fertilizers?
Compost is used as a soil additive when planting new trees, shrubs, vegetables, flowers and lawns. Its rich, organic content improves soil structure and nutrient holding capacity, and gives the soil a rich, dark color and it supplies most of the micronutrients.

Compost cannot really replace fertilizer but it does enhance its effectiveness. Fertilizer contains nutrients, the three primary ones being nitrogen (N), phosphorous (P) and potassium (K) in varying ratios. Each nutrient plays an important part in overall plant growth and vigor. Nitrogen contributes to overall general health and foliage production and growth, Phosphorous promotes a strong root system and boosts flower production and Potassium enhances fruit production.

What is soil pH and how do I test soil?
For most home gardens, soil needs to be tested every 2-3 years. Although many factors such as type and size of particles and amount of organic matter determine a soil's nutrient holding capacity, drainage, and suitability for plant growth, soil pH will indicate whether a soil is acidic, neutral or alkaline. The pH is expressed in a scale from 0-14 where 0 is acid, 7 neutral and 14 is alkaline. Most garden plants in our area do well in a slightly acidic soil with a pH range from 5.5 to 7, although certain plants will have a particular growing preference. A pH reading below 5.5 is quite acidic and is more suitable for growing acid-loving ericaceous plants such as Rhododendron and Azalea. If a pH is over 7 it indicates that the soil is alkaline and more suitable for lawns and certain vegetables.

To determine the pH reading of your garden soil, obtain a home soil-testing kit and follow the instructions to take a soil sample and test it. Since soils vary considerably on a site, it is best to take random soil samples and mix them together to get an average reading. For lawns, take a sample from the top 2-4 inches of soil. If the area to be sampled is for trees and shrubs, a sample taken to the depth of 8-12 inches is recommended. If the soil from your sample is found to be too acidic for the type of plants you want to grow, you will need to adjust the pH by adding lime, or if the pH is too high, it can be lowered with the addition of sulfur.

A complete soil analysis will test for nutrients in addition to pH. The most important nutrients for plant growth include nitrogen, phosphorus, and potassium (N-P-K) although the presence of other minerals called trace elements is necessary for plant growth in lower proportions. If an area in your garden has been used over and over again to grow the same types of plants, i.e. vegetable crops, the soil may become depleted in certain trace elements over time. Contact your local Cooperative Extension Service for information on complete soil testing services available to you.

It is also advisable to test your soil for composition as the types and distribution of particles within a soil will influence its drainage capacity and the availability of nutrients to plant roots. Take a handful of soil, if it feeds gritty, it is mostly sand, if it feels slippery, clay, if crumbly; loam. If there is organic matter present, a black coating will remain on your hands after moistening them and squeezing a handful of soil. Count the number of earthworms in a soil sample, 1' x 1' x 6", if there are at least ten, your soil content is sufficiently organic.

How do I prepare new flower beds for planting?
For healthy plants with strong root development and profuse bloom, proper bed preparation is essential. Aim to achieve good soil drainage and fertility at the outset. First, remove all plant cover such as turf and weeds by digging and cultivating. Any weeds with persistent underground parts may need a chemical treatment with a pre-emergent herbicide. Then dig the bed to a depth of 6 inches for annuals and between 8 and 10 inches for perennials. This encourages the plants to root deeply and establish well from the outset. Work compost into the soil to both improve drainage and hold moisture in the bed before planting. Nutrients such as phosphorous (superphosphate) can be added at this time to help establish the transplants quickly.

What trees and shrubs need spring pruning?
Prune most deciduous trees and needle-leaf evergreens in the late winter or early spring when they are dormant and before new growth begins. Certain deciduous trees such as beech, birch, dogwood, elm, maple and sycamore will bleed excessively if pruned at this time, wait until summer to prune them.

Early-spring flowering shrubs like Azalea, Forsythia, Rhododendron and Spirea need to be pruned just after flowering.

Summer-flowering shrubs that bloom on new wood such as Hydrangea and Buddleia must be pruned in the early spring before new growth starts.

Prune evergreen hedges such as Buxus, Yew and Tsuga in the early spring just before new growth begins.

Finally, prune all roses in early spring except climbers and ramblers; they need pruning only after they flower.

What can I do to prepare now for a possible summer drought?
In the Southeast New York region, the drought of summer 1999 was devastating to many water-thirsty garden plants. Perhaps you have decided to devote more of your garden to drought-tolerant plants. These types of plants can really be the keys to gracefully weathering a sustained summer dry spell with possible water restrictions. There are many native and naturalized landscape plants that grow well under low-water conditions. Contact your local resources such as a botanical garden and cooperative extension service to help you identify the water-conserving plants that will readily grow in your area.

Additional steps include the use of mulches to reduce soil temperature and evapotranspiration rates. Mulches will also insulate plant roots from summer heat and help reduce weeds, which compete with plants for moisture. Keep in mind that fine textured organic mulches such as pine needles and shredded bark hold water better than coarse textured ones.

Now is the best time to plan and install the most effective drip irrigation system equipped with point/source tubing with emitters "punched-in" where plants are located, soaker hoses and/or moveable micro-irrigation sprinklers which gently deliver water only to the roots of your garden plants.

You also may want to reduce the amount of turf areas, as they demand such high-water use with standard sprinkler systems. Replace water demanding turf species with low to moderate-use species. Use turf grasses that may go dormant when unwatered but will green-up again when rainfall returns.

During the summer dry times, follow these water-wise principles:

  • Water all plants including lawn areas early in the morning to minimize evaporation losses. Water all plants less frequently but more thoroughly.
  • Remove weeds that compete for moisture and nutrients.
  • Keep plants pruned and maintained to support optimum health.
Lastly, think ahead about implementing a thorough maintenance plan, and read up on environmentally friendly gardening practices. Enjoy a sound and flourishing water-wise garden this summer!

What are some non-toxic methods of pest and disease prevention and control?
To reduce pest and disease problems, it is recommended that you practice good sanitation and cultural practices in the garden. Remove dead leaves, twigs, flowers and other plant debris so there are no hiding places for pests and pathogens. Prune out diseased and injured plant parts as quickly as possible to halt the spread of disease. Sterilization of pruning equipment after such use will also help to lower disease spread.

Cultural practices such as proper spacing and pruning to encourage good air circulation, selection based on hardiness, site-suitability, disease and pest resistance will go along way to keep plants healthy and stress-free, and therefore more resistant to attack.

Instead of resorting to pesticides if a pest problem exists, first try simple mechanical methods of removal such as hand picking or washing down with water to dislodge the pests. A strong water jet spray from a garden hose is quite effective for this purpose.

If this does not fully solve the problem, use a stronger pest suppressor such as an insectididal soap spray, which disrupts the outer membrane of certain insect pests.